U.S. patent number 8,471,909 [Application Number 13/081,524] was granted by the patent office on 2013-06-25 for driving assistance apparatus.
This patent grant is currently assigned to DENSO CORPORATION. The grantee listed for this patent is Takahiro Ishikawa. Invention is credited to Takahiro Ishikawa.
United States Patent |
8,471,909 |
Ishikawa |
June 25, 2013 |
Driving assistance apparatus
Abstract
In a hand-free driving warning process for a vehicle, when a
grip state of a steering wheel is in a hand-free driving state, and
the vehicle is in a travel state stipulated previously, a danger
degree is derived based on a position of a vehicle compartment
where a non-grip hand exists. In deriving the danger degree, when
the non-grip hand is in a high danger position, a high level is
set; when the non-grip hand exists in a low danger position, a
middle level or a low lever is set. In the low level, any warning
is not outputted; in the middle level, a warning is outputted in a
sound volume smaller than a usual sound volume; and in the high
level, a warning is outputted in the usual sound volume or
greater.
Inventors: |
Ishikawa; Takahiro (Nagoya,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Ishikawa; Takahiro |
Nagoya |
N/A |
JP |
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Assignee: |
DENSO CORPORATION (Kariya,
JP)
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Family
ID: |
44787935 |
Appl.
No.: |
13/081,524 |
Filed: |
April 7, 2011 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20110254956 A1 |
Oct 20, 2011 |
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Foreign Application Priority Data
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Apr 19, 2010 [JP] |
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2010-96166 |
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Current U.S.
Class: |
348/148; 345/647;
382/103 |
Current CPC
Class: |
B60W
40/08 (20130101); B60W 50/14 (20130101); B62D
1/046 (20130101); B60W 2420/42 (20130101) |
Current International
Class: |
H04N
7/18 (20060101); G09G 5/00 (20060101); G06K
9/00 (20060101) |
Field of
Search: |
;348/148 ;345/647
;382/103 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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A-07-25301 |
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Jan 1995 |
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JP |
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A-11-48819 |
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Feb 1999 |
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JP |
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2005-063090 |
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Mar 2005 |
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JP |
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2005-205943 |
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Aug 2005 |
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JP |
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2006123640 |
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May 2006 |
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JP |
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2007-140978 |
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Jun 2007 |
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JP |
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2007-299048 |
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Nov 2007 |
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JP |
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2008-084141 |
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Apr 2008 |
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JP |
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A-2008-122149 |
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May 2008 |
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JP |
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2008-226331 |
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Sep 2008 |
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JP |
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Other References
Japanese Office Action (Notification of Reasons for Refusal) issued
from the Japanese Patent Office dated Mar. 6, 2012 for the
corresponding JP patent application No. 2010-096166 (English
translation attached). cited by applicant .
Yamashita et al., "Efficient Features for Object Recognition,"
Information Proceeding Society, Research Report CVIM 165, pp.
221-236, Nov. 27, 2008. cited by applicant .
Sheikh et al., "On the Sustained Tracking of Human Motion." 8th
IEEE International Conference on Automatic Face and Gesture
Recognition, Sep. 17, 2008. cited by applicant .
Ito et al., "Predicting Driver Operations inside Vehicles." 8th
IEEE International Conference on Automatic Face and Gesture
Recognition, Sep. 17, 2008. cited by applicant.
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Primary Examiner: Perungavoor; Sath V
Assistant Examiner: Xu; Xiaolan
Attorney, Agent or Firm: Posz Law Group, PLC
Claims
What is claimed:
1. A driving assistance apparatus for a vehicle, comprising: a grip
state detection section configured to detect a grip state of a
steering wheel in a compartment of the vehicle; an image
acquisition section configured to acquire a captured image of the
compartment that covers a possible action range of a person who is
seated in a driver's seat; a position specification section
configured to specify, based on a captured image acquired by the
image acquisition section, a position where a non-grip hand exists,
the non-grip hand being a hand that is separate from the steering
wheel, on condition that (i) the grip state of the steering wheel
is in a hand-free state, in which at least either of two hands is
separate from the steering wheel as a result of detecting of the
grip state detection section, and (ii) a travel state of the
vehicle is within a stipulated travel state, which is
predetermined; a danger derivation section configured to derive a
danger degree such that the danger degree comes to have a greater
value as a degree of a danger against driving of the vehicle
becomes higher because the non-grip hand exists in a position
specified by the position specification section; and a warning
section configured to execute an output of a warning in a weaker
state as the danger degree derived by the danger derivation section
comes to have a smaller value, wherein: the danger derivation
section classifies a plurality of positions in the compartment in
the vehicle based on danger degrees, and defines previously a low
danger position within the positions classified, wherein the danger
degree has a value smaller than a reference value when the non-grip
hand exists in the low danger position; and the danger derivation
section derives the danger degree such that when the non-grip hand
exists in the low danger position, the danger degree has a value
smaller as compared with a case that the non-grip hand exists in a
high danger position, which is within the positions classified in
the compartment and is other than the low danger position.
2. The driving assistance apparatus according to claim 1, wherein
the danger derivation section derives the danger degree such that
the danger degree comes to have a smaller value as a non-grip hand
existence duration for which the non-grip hand continues to exist
in the low danger position becomes shorter.
3. The driving assistance apparatus according to claim 2, wherein
the danger derivation section derives the danger degree such that
when the non-grip hand existence duration relative to the low
danger position, where the non-grip hand exists, is shorter than a
predetermined value, the danger degree has a minimum value.
4. The driving assistance apparatus according to claim 1, wherein
the danger derivation section derives the danger degree such that
when the non-grip hand exists in the high danger position, the
danger degree comes to have a greater value as a non-grip hand
existence duration, for which the non-grip hand continues to exist
in the high danger position, becomes longer.
5. The driving assistance apparatus according to claim 1, wherein
the danger derivation section derives the danger degree such that
when the non-grip hand exists in the high danger position, the
danger degree comes to have a greater value as the high danger
position is farther away from the driver's seat.
6. The driving assistance apparatus according to claim 1, wherein:
the high danger position is a position, where a target object
manipulated by the non-grip hand exists; and the danger derivation
section derives the danger degree such that when the non-grip hand
exists in the high danger position, the danger degree comes to have
a greater value as a duration, for which the non-grip hand
manipulates the target object in the high danger position and then
grips the steering wheel, is estimated to become longer.
7. The driving assistance apparatus according to claim 1, wherein:
the high danger position is a position where a target object
manipulated by the non-grip hand exists; and the danger derivation
section derives the danger degree such that when the non-grip hand
exists in the high danger position, the danger degree comes to have
a greater value as a duration, for which the driver moves a sight
line away from a heading direction of the vehicle when manipulating
the target object in the high danger position, is estimated to
become longer.
8. The driving assistance apparatus according to claim 1, wherein
the position specification section determines whether a position
where the non-grip hand exists is the low danger position, and
defines a high danger position, which is within the positions
classified in the compartment and is determined not to be the low
danger position.
9. The driving assistance apparatus according to claim 1, wherein
The danger derivation section defines as the low danger position,
at least one of (i) an armrest provided in the vehicle, (ii) a
window frame in the vehicle, and (iii) a driver's upper thigh.
10. The driving assistance apparatus according to claim 1, wherein
the warning section prohibits an output of a warning when the
danger degree derived by the danger derivation section is equal to
or less than a predetermined value.
11. The driving assistance apparatus according to claim 1, wherein
the stipulated travel state includes a travel state where the
hand-free state during driving of the vehicle is evitable.
12. A program product, stored in a non-transitory computer readable
storage medium, comprising instructions for execution by a
computer, the instructions including a computer-implemented method
in a driving assistance apparatus for a vehicle for deriving a
danger degree to warn against driving manipulation of the vehicle,
the driving assistance apparatus including: a grip state detection
section configured to detect a grip state of a steering wheel in a
compartment of the vehicle; and an image acquisition section
configured to acquire a captured image of the compartment that
covers a possible action range of a person who is seated in a
driver's seat, the instructions for implementing the steps of:
specifying, based on a captured image acquired by the image
acquisition section, a position where a non-grip hand exists, the
non-grip hand being a hand that is separate from the steering
wheel, on condition that (i) the grip state of the steering wheel
is in a hand-free state, in which at least either of two hands is
separate from the steering wheel as a result of detecting of the
grip state detection section, and (ii) a travel state of the
vehicle is within a stipulated travel state, which is
predetermined; deriving a danger degree such that the danger degree
comes to have a greater value as a degree of a danger against
driving of the vehicle becomes higher because the non-grip hand
exists in the position specified; and executing an output of a
warning in a weaker state as the danger degree derived comes to
have a smaller value, wherein in the deriving step, a plurality of
positions are classified in the compartment in the vehicle based on
danger degrees, and a low danger position is defined previously
within the classified positions, wherein the danger degree has a
value smaller than a reference value when the non-grip hand exists
in the low danger position; and in the deriving step, the danger
degree is derived such that when the non-grip hand exists in the
low danger position, the danger degree has a smaller value as
compared with a case that the non-grip hand exists in a high danger
position, which is within the positions classified in the
compartment and is other than the low danger position.
Description
CROSS REFERENCE TO RELATED APPLICATION
The present application is based on and incorporates herein by
reference Japanese Patent Application No. 2010-96166 filed on Apr.
19, 2010.
FIELD OF THE INVENTION
The present invention relates to a driving assistance apparatus
which outputs a warning to warn a vehicle driver against driving
the vehicle with his/her hand free.
BACKGROUND OF THE INVENTION
[Patent document 1] JP-A-2008-122149
For instance, Patent document 1 recites a conventionally known
apparatus to detect whether a steering wheel of a vehicle is held
or gripped with both hands of a driver, based on a signal inputted
from a sensor in-bedded in the steering wheel. In the apparatus
recited in Patent document 1, when it is detected that the steering
wheel is held by one hand of the driver, a travel state of the
vehicle is determined whether to be within-stipulated or
without-stipulated. The without-stipulated travel state is defined
as a travel state where the driving manipulation with the steering
wheel gripped by only one hand is inevitable. The within-stipulated
travel state is other than the without-stipulated travel state.
When the determined travel state is within-stipulated warning is
outputted so as to warn the driver of driving the vehicle more
safely.
In Patent document 1, the without-stipulated travel state includes
the following: when the vehicle is moved backward; when the vehicle
is rotated; when an in-vehicle instrument necessary for driving the
vehicle (for example, a shift lever, or a blinker, a head lamp
switch) is manipulated; and when the vehicle is in traffic
congestion.
The state, where a driver performs a driving manipulation while
holding or gripping the steering wheel with a single hand, may
includes a state where the driver puts the hand, which is not
gripping the steering wheel, on an armrest or window frame in the
vehicle while performing the driving manipulation. In such a case,
while relaxing moderately, the driver of the vehicle still
concentrates on the driving manipulation, thereby usually enabling
the vehicle to be driven safely in many cases.
Although the vehicle is driven still safely even with the steering
wheel held with a single hand, such a state is defined as not
according with the without-stipulated travel state in Patent
document 1 thereby outputting a warning to the driver. That is, the
warning is outputted to the driver concentrating on driving
manipulation. The sense of incongruity is thus given to the driver;
by contrast, the warning may lower the concentration of the driver
on the driving manipulation.
That is, in Patent document 1, there is a disadvantage or problem
that a warning is not suitably outputted to the driver in
consideration of various states of the driver taking place at the
time when the steering wheel of the vehicle is held with a single
hand.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a technology to
output appropriately a warning to a driver according to a state of
the driver with a driving assistance apparatus that outputs a
warning against driving manipulation with a hand free.
To achieve the above object, according to an example of the present
invention, a driving assistance apparatus for a vehicle is provided
as follows. A grip state detection section is configured to detect
a grip state of a steering wheel in a compartment of the vehicle.
An image acquisition section is configured to acquire a captured
image of the compartment that covers a possible action range of a
person who is seated in a driver's seat. A position specification
section is configured to specify, based on a captured image
acquired by the image acquisition section, a position where a
non-grip hand exists, the non-grip hand being a hand that is
separate from the steering wheel, on condition that (i) the grip
state of the steering wheel is in a hand-free state, in which at
least either of two hands is separate from the steering wheel as a
result of detecting of the grip state detection section, and (ii) a
travel state of the vehicle is within a stipulated travel state,
which is predetermined. A danger derivation section is configured
to derive a danger degree such that the danger degree comes to have
a greater value as a degree of a danger against driving of the
vehicle becomes higher because the non-grip hand exists in a
position specified by the position specification section. A warning
section is configured to execute an output of a warning in a weaker
state as the danger degree derived by the danger derivation section
comes to have a smaller value.
Under such a configuration, the position where a driver's hand not
gripping the steering wheel is located (referred to as the position
of the non-grip hand) is used to estimate the degree of the
concentration of the driver on the driving manipulation, thereby
enabling a warning to be suitably outputted.
As a result, the driver using the driving assistance apparatus can
maintain the concentration on the driving manipulation of the
vehicle, without having a sense of incongruity in the warning
outputted in the case of driving with a single hand separate from
the steering wheel (i.e., in the case of the hand-free
driving).
According to another example of the present invention, a method
being computer-implemented is provided in a driving assistance
apparatus for a vehicle for deriving a danger degree to warn
against driving manipulation of the vehicle. The driving assistance
apparatus includes a grip state detection section configured to
detect a grip state of a steering wheel in a compartment of the
vehicle; and an image acquisition section configured to acquire a
captured image of the compartment that covers a possible action
range of a person who is seated in a driver's seat. The method
includes (i) specifying, based on a captured image acquired by the
image acquisition section, a position where a non-grip hand exists,
the non-grip hand being a hand that is separate from the steering
wheel, on condition that (a) the grip state of the steering wheel,
is in a hand-free state, in which at least either of two hands is
separate from the steering wheel as a result of detecting of the
grip state detection section, and (b) a travel state of the vehicle
is within a stipulated travel state, which is predetermined; (ii)
deriving a danger degree such that the danger degree comes to have
a greater value as a degree of a danger against driving of the
vehicle becomes higher because the non-grip hand exists in the
position specified; and (iii) executing an output of a warning in a
weaker state as the danger degree derived comes to have a smaller
value.
Relating to this example, as yet another example of the present
invention, a program product stored in a non-transitory computer
readable storage medium comprising instructions for execution by a
computer, the instructions including the above method that is
computer-implemented.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features, and advantages of the
present invention will become more apparent from the following
detailed description made with reference to the accompanying
drawings. In the drawings:
FIG. 1 is a block diagram showing an overall configuration of a
driving assistance apparatus according to embodiments of the
present invention;
FIG. 2 is a diagram explaining an example of an image captured by
an image processing device included in the driving assistance
apparatus;
FIG. 3 is a flowchart diagram illustrating a hand-free driving
warning process according to a first embodiment;
FIG. 4 is a flowchart diagram illustrating a danger estimation
process according to the first embodiment;
FIG. 5 is a diagram illustrating an outline of a danger estimation
map according to the first embodiment;
FIG. 6 is a flowchart diagram illustrating a danger estimation
process according to a second embodiment;
FIG. 7 is a diagram illustrating an outline of a danger estimation
map according to the second embodiment; and
FIGS. 8A, 8B are diagrams each illustrating an outline of a danger
estimation map according to a modification of the second
embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereafter, description will be given to embodiments of the present
invention with reference to the drawings.
First Embodiment
<Configuration of Driving Assistance Apparatus>
A schematic configuration of a driving assistance apparatus
according to embodiments of the present invention is illustrated in
FIG. 1.
This driving assistance apparatus 1 is mounted in a subject
vehicle, while determining a grip state of a steering wheel 71
(also referred to a wheel grip state) in the vehicle, i.e., whether
the steering wheel is gripped with one hand or two hand (refer to
FIG. 2). When it is determined that the wheel grip state is a state
where the steering wheel 71 is held or gripped with a single hand,
a position where a non-grip hand exists is at least specified; the
non-grip hand signifies a hand that is not gripping the steering
wheel 71. Based on the specified position where the non-grip hand
is existing, a danger degree is derived; a warning is then
outputted according to the danger degree.
In order to realize the above, the driving assistance apparatus 1
includes the following: an in-vehicle sensor switch group 10 that
detect, of the subject vehicle a travel state including at least a
grip state of the steering wheel 71; an image processing device 30
to specify at least a non-grip hand position which is a position
where the driver's hand exists based on a captured image of a
vehicle compartment; and a driving assistance device 40 to derive a
danger degree based on a travel state of the subject vehicle
detected by the in-vehicle sensor switch group 10, and the non-grip
hand position specified by the image processing device 30, thereby
outputting a warning according to the derived danger degree.
<Image Processing Device>
The image processing device 30 includes a capture portion 31 to
capture a digital image, and an image processor 35 to apply image
processing to an image captured (also referred to as a captured
image) by the capture portion 31 thereby recognizing the position
where the driver's hand exists.
As illustrated in FIG. 2, the capture portion 31 is provided to
capture an image in a capture range that includes at least a
possible action range of the driver in a vehicle compartment. The
possible action range signifies a space of the vehicle compartment
where a person seated in the driver's seat of the subject vehicle
can behave (also referred to as a possible action range). The
capture portion 31 is fixed in a position predetermined in the
compartment (for example, near a rearview mirror). For instance, in
the present embodiment, the capture range covers the following: the
steering wheel 71 of the subject vehicle; the window frame 72 of
the side of the driver's seat; armrests 73, 74; a shift lever 75; a
rearview mirror 76; a passenger seat 77; an air-conditioner
manipulation portion 78 provided in an instrument panel; an input
reception portion 79 of a navigation apparatus; a glove box 80; a
head region 81 that is a region where the head of the person seated
in the driver's seat exists; and an upper thigh region 82 that is a
region where the upper thigh (defined as a portion between a knee
and a waist) of the person seated in the driver's seat exists.
The capture portion 31 may be a well-known light camera or a
well-known infrared camera. The capture portion 31 may be provided
with a lighting which irradiates the capture range with infrared
light. The image processor 35 includes mainly a well-known
microcomputer having at least a storage portion 36, a memory 37,
and an arithmetic unit 38.
The storage portion 36 is a non-volatile memory such as a flash
memory to enable rewrite of memory data. In addition, the memory 37
stores temporarily data produced in a course of processing. The
captured image from the capture portion 31 is temporarily stored in
the memory 37. The arithmetic unit 38 executes a processing program
thereby executing image processing to a captured image stored in
the memory 37.
The image processing according to the present embodiment includes a
position recognition process, which recognizes a region (i.e.,
coordinates) in the captured image in which the driver's hand and
lower arm exist. The position recognition process is made by well
known various technologies; thus, detailed explanation is omitted.
The present embodiment may use the following technology, which
derives a predetermined feature quantity from a captured image, and
collates the derived feature quantity with a discrimination circuit
indicating a person's hand (e.g., a part from a wrist to a
fingertip) and lower arm (a part from an elbow to a wrist). In the
above technology, the well-known Haar-Like feature is generally
used as a feature quantity; the discrimination circuit is generated
by learning the feature quantity with a well-known machine learning
(for example, AdaBoost).
The image processing according to the present embodiment further
includes a position determination process which specifies, as a
position in the compartment where a driver's hand exists, a
position of the compartment corresponding to the region
(coordinates) in, the captured image recognized in the position
recognition processing. The position in the compartment recognized
in the position determination process is one of the following
positions: the steering wheel 71 of the subject vehicle; the window
frame 72 of the side of the driver's seat; the armrests 73, 74; the
shift lever 75; the rearview mirror 76; the passenger seat 77; the
air-conditioner manipulation portion 78; the input reception
portion 79 of the navigation apparatus; the glove box 80; the head
region 81; the upper thigh region 82; and another position other
than the above positions 71 to 82.
That is, the image processing device 30 of the present embodiment
specifies, from the captured image the position in the vehicle
compartment where the driver's hand exists, and outputs the
specified result to the driving assistance device 40.
<In-Vehicle Sensor Switch Group>
The in-vehicle sensor switch group 10 contains a steering angle
sensor 11, a steering wheel grip sensor 12, a vehicle velocity
sensor 13, a shift position sensor 14, and an indispensable
instrument manipulation detection portion 20. These sensors 11 to
14 and the indispensable instrument manipulation detection portion
20 output, as detection signals, detection results to the driving
assistance device 40.
The steering angle sensor 11 detects a steering angle of the
subject vehicle. The velocity sensor 13 detects a velocity of the
subject vehicle. The shift position sensor 14 detects a position of
the shift lever 75 (also referred to as a shift position).
Furthermore, the wheel grip sensor 12 detects a grip state of the
steering wheel 71. The wheel grip sensor 12 of the present
embodiment is configured to arrange two sensing portions 12A, 12B
in portions in the steering wheel 71 gripped by the left hand and
right hand, respectively; the sensing portions 12A, 12B are, for
instance, pressure sensors or touch sensors, of which signals are
turned into a high level when a people's skin contacts. That is,
the detection signal outputted from each of the sensing portions
12A, 12B in the wheel grip sensor 12 becomes in a high level when
the corresponding portion of the steering wheel 71 is gripped, or
becomes in a low level when the corresponding portion of the
steering wheel 71 is not gripped.
The indispensable instrument manipulation detection portion 20
detects that an indispensable instrument, which is an instrument
indispensable for the driving operation of the vehicle, is
manipulated so as to activate or stop an operation. This
indispensable instrument manipulation detection portion 20 contains
the shift lever manipulation sensor 21, of which the detection
signal is turned into a high level when the hand contacts the shift
lever 75.
Furthermore, the indispensable instrument manipulation detection
portion 20 includes a lamplight switch 22, a direction indicator
switch 23, a horn switch 24, and a windshield wiper switch 25.
Those switches 22 to 25 each are turned on and turned off when a
manipulation is made to a manipulation portions or means arranged
in the steering wheel 71 or a steering wheel column. The lamplight
switch 22 is associated with a head light of the subject vehicle as
an indispensable instrument. The direction indicator switch 23 is
associated with a direction indicator of the subject vehicle as an
indispensable instrument. The horn switch 24 is associated with a
horn of the subject vehicle as an indispensable instrument. The
wiper switch 25 is associated with a wiper of the subject vehicle
as an indispensable instrument.
<Driving Assistance Device>
The driving assistance device 40 includes a position detection
portion 41, an information communications portion 42, a display
portion 43, an audio output portion 44, an input reception portion
79, a storage portion 46, and a navigation electronic control unit
50 (also referred to as a navigation ECU 50).
The position detection portion 41 detects a present position and
heading direction of the subject vehicle and at least includes a
well-known GPS receiver, a gyro sensor, and a geomagnetic sensor.
In addition, the information communications portion 42 is to
acquire information from a communications device provided in a road
via dedicated wireless communications or public communications
network; the acquired information includes traffic congestion
information which at least indicates the presence or absence of the
traffic congestion arising on the vicinity of the present position
of the subject vehicle and the starting position and ending
position of the traffic congestion.
Furthermore the display portion 43 is, for instance, a liquid
crystal display to display an image according to a control signal
from the navigation ECU 50. The audio output, portion 44 is, for
instance, a speaker to convert a control signal from the navigation
ECU 50 into a sound and output the sound. The input reception
portion 79 is, for instance, a touch panel integrated into the
display portion 43 or a key provided around the display portion 43
to receive various instructions from an occupant.
The storage portion 46 is a rewritable non-volatile storage device
or media such as a hard disk drive or a flash memory. The storage
portion 46 stores previously map data, audio data for guidance
voice recognition data, etc. The map data includes node data, link
data, cost data, background data, road data, geographical data,
name data, mark data, intersection data, facility data, etc.
Furthermore, the navigation ECU 50 mainly includes a well-known
microcomputer, which has at least a ROM 51 storing data whose
memory contents need to be held even if the power source is
disconnected, a RAM 52 storing data temporarily, a CPU 53 executing
processing according to the program stored in the ROM 51 or RAM
52.
In addition, the navigation ECU 50 receives not only the detection
signal from the in-vehicle sensor switch group 10, but also an
ignition (IG) signal. The navigation ECU 50 executes the processing
program, thereby providing a well-known navigation function of a
navigation apparatus, which performs a route guidance to a
destination designated according to an input from an outside based
on the present position and heading direction of the subject
vehicle calculated from the output signal from the position
detection portion 41, and the map data stored in the storage
portion 46.
Furthermore, the navigation ECU 50 derives a danger degree based on
the travel state of the subject vehicle and the position where the
hand of the driver of the subject vehicle is located, and executes
a hand-free driving warning process to output a warning according
to the derived danger degree.
<Hand-Free Driving Warning Process>
Next, the hand-free driving warning process (also referred to as
the one-hand driving warning process) executed by the navigation
ECU 50 is explained. The hand-free driving warning process starts
an execution of processing when the IG signal is inputted, and
repeats the execution with predetermined time intervals.
It is further noted that a flowchart or the processing of the
flowchart in the present application includes sections (also
referred to as steps), which are represented, for instance, as
S110. Further, each section can be divided into several
sub-sections while several sections can be combined into a single
section. Furthermore, each of thus configured sections can be
referred to as a means or unit and achieved not only as a software
device but also as a hardware device.
With reference to FIG. 3, when the hand-free driving warning
process is started, it is determined whether the grip state of the
steering wheel 71 corresponds to a hand-free driving state in which
at least one hand is separated from the steering wheel 71 based on
the detection signal from the wheel grip sensor 12 (S110).
For instance, at S110 of the present embodiment, when the level of
the detection signal from at least one of the sensing portions 12A,
12B of the wheel grip sensor 12 is in a low level, the hand-free
driving state is determined (also referred to as a one-hand driving
state). In contrast, when both the levels of the detection signals
from the sensing portions 12A, 12B are in the high level, a
both-hands driving state in which the steering wheel 71 is gripped
with both the hands of the driver is determined.
When it is determined that the grip state of the steering wheel 71
is a hand-free driving state (S110 YES), the processing proceeds to
S120. At S120, it is determined whether the travel state of the
subject vehicle accords with a within-stipulated travel state that
is other than a without-stipulated travel state, based on the
detection signal from the in-vehicle sensor switch group 10. The
without-stipulated travel state is defined as a travel state in
which a hand-free driving manipulation is permitted as being
inevitable. In other words, the within-stipulated travel state is
defined as a travel state in which a hand-free driving manipulation
is unpermitted as being evitable.
In the present embodiment, the without-stipulated travel state in
the present embodiment includes, for instance, the following: the
backward moving state where the subject vehicle is moved
backwardly; the rotating state where the subject vehicle is
rotated; the indispensable instrument manipulating state where an
indispensable instrument is manipulated; the in-traffic congesting
state where the subject vehicle is involved in the traffic
congestion; and the slow speed state where the subject vehicle is
in the low speed.
At S120 of the present embodiment, it is determined whether the
travel state of the subject vehicle accords with a
without-stipulated travel state using the technique described in
JP-A-2008-122149. That is, when the detection signal from the shift
position sensor 14 indicates that the shift position is "R" (that
is, backward movement), it is determined that the present travel
state of the subject vehicle accords with the backward moving
state. In addition, when the steering angle detected by the
steering angle sensor 11 is greater than a predetermined value or
angle, it is determined that the travel state of the subject
vehicle accords with the rotating state. After it is determined
that the grip state of the steering wheel 71 is a hand-free driving
state at S110, the detection signal from the indispensable
instrument manipulating detection portion 20 changes within a
predetermined period. In this case, it is determined that the
travel state of the subject vehicle accords with the indispensable
instrument manipulating state. Furthermore, when the present
position of the subject vehicle is located in the road range from
the start position to the end position of the traffic congestion
acquired in the information communications portion 42, it is
determined that the travel state of the subject vehicle accords
with the traffic congesting state. In addition, when the vehicle
speed detected by the vehicle velocity sensor 13 is less than a
predetermined value, it is determined that the travel state of the
subject vehicle accords with the slow speed state.
When the travel state of the subject vehicle does not accord with
the without-stipulated travel state as a result of the
determination at S120, namely, when the travel state accords with
the within-stipulated travel state (S120: YES), the processing
proceeds to S130. At S130, a hand-free duration is obtained. The
hand-free duration is a duration or time length for which a
non-grip hand, which is a hand not gripping the steering wheel 71,
is continuously separated from the steering wheel 71. At the same
time, a position where the non-grip hand exists (also referred to
as a non-grip hand position) is specified, and the danger
estimation process which estimates a danger degree based on the
specified position and the obtained hand-free duration (S130).
<Danger Estimation Process>
The danger estimation process started at S130 of the hand-free
driving warning process is explained.
With reference to FIG. 4, when the danger estimation process is
started, positions at which the left hand and the left hand of the
driver exist (also referred to left and right hand positions) are
obtained within the vehicle compartment from the image processing
device 30 (S210). Then, based on the left hand position and the
right hand position acquired at S210, it is determined whether
there is a non-grip hand located in a predetermined first low
danger position A (window frame 72 in the present embodiment)
(S220). It is noted that a low danger position is where the driver
puts a hand in relaxing himself/herself while performing the
driving manipulation. When it is determined that there is no
non-grip hand existing in the first low danger position A (S220:
NO), it is determined whether there is a non-grip hand existing in
a predetermined second low danger position B (armrests 73, 74 in
the present embodiment) (S230).
When it is determined that there is no non-grip hand existing in
the second low danger position A (S230: NO), it is determined
whether there is a non-grip hand existing in a predetermined third
low danger position C (upper thigh 82 in the present embodiment)
(S240). When it is determined that there is no non-grip hand
existing in the third low danger position C (S240: NO), a dangerous
hand-free duration, which is one type of the hand-free duration, is
incremented by a predetermined time (S250).
Thus, the non-grip hand is estimated to exist in the high danger
position which is other than the low danger position A to C; the
danger degree corresponding to the dangerous hand-free duration is
set by acquiring from the danger estimation map prepared previously
(S260). The danger estimation map in the present embodiment may be
previously obtained by an experiment etc. As illustrated in FIG. 5,
the association between the dangerous hand-free duration and the
danger degree is provided such that as the dangerous hand-free
duration becomes longer, the value of the danger degree becomes
larger (i.e., exhibiting a monotone increase). The association
between the dangerous hand-free duration and the danger degree may
be provided such that the danger degree varies in a straight line
in proportion to the dangerous hand-free duration; or it may be
varied in a curved line, or in a step-by-step (i.e.,
step-wise).
Usually, when the non-grip hand exists in the high danger position
the driver manipulates the in-vehicle instrument located in the
high danger position in many cases; thereby, the dangerous
hand-free duration becomes long. Therefore, the danger degree
acquired at S260 in the present embodiment has a value that becomes
greater in "High" level as the dangerous hand-free duration becomes
longer.
Then, the present danger estimation process is ended, advancing the
processing to S160 of the hand-free driving warning process. If the
non-grip hand exists in any one of the low danger positions A, B,
and C as a result of determination at S220, S230, and S240 (S220:
YES, S230: YES, or S240: YES), a permitted hand-free duration,
which is one type of the hand-free duration, is incremented by a
predetermined time (S270). Then, it is determined whether the
permitted hand-free duration is equal to or greater than a
predetermined permitted time or duration (for example, 30 minutes)
(S280). The permitted hand-free duration may be also referred to as
a non-grip hand existence duration for which the non-grip hand
continues to exist in the low danger position.
When the permitted hand-free duration is equal to or greater than
the permitted duration as a result of determination at S280 (S280:
YES), the danger degree is set to "Middle" level (S290). In
contrast, when the permitted hand-free duration is less than the
permitted duration as a result of determination at S280 (S280: NO),
the danger degree is set to "Low (minimum)" level (S300).
That is, in the present embodiment, when the non-grip hand exists
in the low danger position, there is a possibility that the driver
is driving the subject vehicle in a relaxed state, thereby setting
the danger degree to "Low level (minimum)." However, even if the
non-grip hand exists in the low danger position, the duration for
which the non-grip hand exists continuously in the low danger
position may become longer. In this case, the danger degree in
driving the subject vehicle becomes higher; the danger degree comes
to be set to the "Middle" level greater than the "Low" level.
Then, the present danger estimation process is ended, advancing the
processing to S160 of the hand-free driving warning process. The
explanation is returned to the flowchart in FIG. 3 regarding the
hand-free driving warning process. When it is determined at S120
that the travel state of the subject vehicle accords with the
without-stipulated travel state, namely, when the travel state does
not accord with the within-stipulated travel state (S120: NO), the
processing proceeds to S140. When it is determined at S110 that the
grip state of the steering wheel 71 is the both-hands driving
state, the processing also advances to S140.
At S140, the hand-free duration or time length (in this case, both
the dangerous hand-free duration and the permitted hand-free
duration) are initialized; namely, the duration is set to zero (0)
in the present embodiment. Then, the danger degree is set to the
"Low (Minimum)" level (S150) That is, when the grip state of the
steering wheel 71 is both-hands driving state, the subject vehicle
is determined to be derived safely, thereby setting the danger
degree to the minimum value. Further, under the condition that it
is determined that the travel state of the subject vehicle accords
with the without-stipulated travel state, since the duration of the
non-grip state of the steering wheel 71 is estimated to be short,
or since the travel state of the subject vehicle is estimated to be
a safe travel state, the danger degree is set to the minimum
value.
Then, a warning is outputted via the display portion 43 and the
audio output portion 44, while the strength of the warning
outputted is controlled to be proportional to the value in the
level of the danger degree (S160). For instance, at S160 of the
present embodiment, warnings are outputted as follows: when the
danger degree is of the maximum value in the "HIGH" level, the
warning is outputted in "VERY STRONG" level; when the danger degree
is of the minimum value in the "HIGH" level, the warning is
outputted in "USUAL" level; when the danger degree is in the
"MIDDLE" level, the warning is outputted in "WEAK" lower than
"USUAL" level; and when the danger degree is in the "LOW (MINIMUM)"
level, the warning is not outputted, namely, the output of the
warning is prohibited. For instance, as the danger degree is
higher, the warning outputted from the audio output portion 44 has
an audio volume in higher level; simultaneously, as the danger
degree is higher, the warning message displayed in the display
portion 43 becomes stronger or stricter.
Then, the present hand-free driving warning process is ended; the
processing stands by until the hand-free driving warning process is
re-started (that is until a predetermined time passes). As
mentioned above, in the hand-free driving warning process according
to the present embodiment, when the grip state of the steering
wheel 71 is the hand-free driving state and, simultaneously, the
travel state of the subject vehicle accords with the
within-stipulated travel state, the danger degree is derived based
on the position in the vehicle compartment where the non-grip hand
exists. In such derivation of the danger degree, when the non-grip
hand exists in the high danger position, the danger degree is set
up such that as the dangerous hand-free duration is longer, the
value becomes greater in the "HIGH" level. In contrast, when the
non-grip hand exists in the low danger position, the danger degree
is set to the "MIDDLE" level or the "LOW" level.
When the danger degree is in the "LOW" level, the warning is not
outputted; when the danger degree is in the "MIDDLE" level, the
warning is outputted in a sound volume weaker or lower than that of
"USUAL" level; and when the danger degree is in the "HIGH" level,
the warning is outputted in a sound level stronger than "USUAL"
level.
Effect of First Embodiment
According to the driving assistance apparatus 1 of the present
embodiment, the warning can be outputted in a suitable strength
according to the position where the driver's non-grip hand exists,
or according to the degree of the driver's concentration on the
driving manipulation on condition that the grip state of the
steering wheel 71 is a hand-free driving state.
In particular, in the hand-free driving warning process of the
present embodiment, when the non-grip hand exists in the low danger
position, and, simultaneously, the permitted hand-free duration is
less than the predetermined permitted duration, the warning itself
is not outputted. Thus, the driver, who drives the subject vehicle
while putting the non-grip hand on the low danger position, can be
concentrated on driving manipulation of the vehicle without need to
be conscious of a warning.
Furthermore the hand-free driving warning process of the present
embodiment features as follows. When the permitted hand-free
duration is greater than the predetermined permitted duration even
on condition that the non-grip hand exists in the low danger
position, or when the non-grip hand exists in the high danger
position, the warning is outputted with the strength proportional
to the danger degree. The driver of the subject vehicle can
recognize that the danger degree is increased by the driver's
action.
Thus, according to the driving assistance apparatus 1, the driver
of the subject vehicle can make an effort to drive the subject
vehicle safely, without having the sense of discomfort or
incongruity against the warning outputted in the case of the
hand-free driving state. Further, in the danger estimation process
of the driving assistance apparatus 1, the positions where the
non-grip hand exists are determined in respect of two statuses
(binary values) of the high danger position and the low danger
position. Accordingly, in the danger estimation process of the
driving assistance apparatus 1, the processing load for specifying
the positions of the non-grip hand can be prevented from
increasing.
Second Embodiment
The following describes a second embodiment. The driving assistance
apparatus of the present embodiment differs from that of the first
embodiment in that the processing of the danger estimation process.
Accordingly, in the driving assistance apparatus according to the
present embodiment, the same configuration or processing as that of
the first embodiment is omitted from the explanation while the
identical reference numbers are assigned. The explanation focuses
on the Processing of the danger estimation process different from
that of the first embodiment.
<Danger Estimation Process>
With reference to FIG. 6, the danger estimation process of the
present embodiment takes place as follows. When the danger
estimation process is started at S130 of the hand-free driving
warning process, positions at which the left hand and right hand of
the driver exist (also referred to left and right hand positions)
are obtained, respectively, within the vehicle compartment from the
image processing device 30 (S510).
Then, a non-grip hand that does not grip the steering wheel 71 is
determined from the obtained positions of the both hands; it is
determined whether the non-grip hand exists in a low danger
position out of the positions in the vehicle compartment (S520).
Similar to the first embodiment, the low danger position indicates
a position at which a driver places the non-grip hand when relaxing
during the driving. A window frame 72, armrests 73, 74, and an
upper thigh area 82 are defined as a low danger position.
When it is determined that the non-grip hand does not exist in the
low danger position (S520 NO), i.e., if it exists in the high
danger position (S520: NO), the processing proceeds to S570
mentioned later. In contrast, when it is determined that the
non-grip hand exists in the low danger position (S520: YES), a
permitted hand-free duration, which is one type of the hand-free
duration, is incremented by a predetermined time (S530). Then, it
is determined whether the permitted hand-free duration is equal to
or greater than a predetermined permitted duration (for example, 30
minutes) (S540).
When the permitted hand-free duration is equal to or greater than
the permitted duration as a result of determination at S540 (S540:
YES), the danger degree is set to "Middle" level (S550). In
contrast, when the permitted hand-free duration is less than the
permitted duration as a result of determination at S540 (S540: NO),
the danger degree is set to "Low (minimum)" level (S560).
Then, the present danger estimation process is ended, advancing the
processing to S160 of the hand-free driving warning process. In
contrast, when the non-grip hand exists in the high danger position
(S520: NO), a position (referred to a present existing position Pn)
where the non-grip hand exists is specified (S570). Out of the
danger hand-free durations respectively corresponding to detectable
positions in the vehicle compartment, the danger hand-free
durations other than that of the present existing position Pn are
initialized (to "0" zero in the present embodiment) at S580.
Herein, the detectable positions each are a position in the vehicle
compartment that can be specified by a position determination
process. Furthermore, the danger hand-free duration corresponding
to the present existing position Pn is incremented by a
predetermined time (S590).
Next, the danger degree corresponding to the association between
(i) the present existing position Pn and (ii) the danger hand-free
duration is set by acquiring from the danger estimation map
prepared previously (S600). The danger estimation map in the
present embodiment may be previously obtained by an experiment etc.
As illustrated in FIG. 7, the association between the danger
hand-free duration and the danger degree is provided such that as
the danger hand-free duration becomes longer, the value of the
danger degree becomes greater. The association between the danger
hand-free duration and the danger degree may be provided such that
the danger degree varies in a straight line in proportion to the
danger hand-free duration; or it may be varied in a curved line, or
in a step-by-step.
Furthermore, the danger estimation map of the present embodiment
indicates the association such that as the detectable position
becomes farther away from the driver's seat, the danger degree
becomes higher. For example, out of the detectable positions, the
passenger seat 77 and the glove box 80 are defined as a high danger
position P1; the air-conditioner manipulation portion 78 and the
input reception portion 79 of the navigation apparatus is defined
as a high danger position P2; and the head area 81 is defined as a
high danger position P3. In the danger estimation map exemplified
in FIG. 7, the association is made such that the danger degree
increases in the ascending order of the high danger position P3,
the high danger position P2, and the high danger position P1.
That is, when the non-grip hand exists in the high danger position
P1, P2, the driver tends to be manipulating an in-vehicle
instrument located in the positions P1, P2 in many cases. When the
non-grip hand exists in the high danger position P3, the driver
tends to be manipulating the goods (for example, food and drink,
tobacco, or cellular phone) brought into the vehicle compartment,
i.e., be during the eating, drinking, smoking, or calling). In the
cases, the danger degree against the driving manipulation of the
subject vehicle becomes higher as the movement amount of the body
for the driver to cause the non-grip hand to exist in the high
danger position becomes greater. Thus as the detectable position
becomes farther away from the driver's seat, the danger degree
becomes higher.
Further, in the cases that the driver is during manipulating an
in-vehicle instrument, eating, drinking, smoking, or calling, the
dangerous hand-free duration becomes longer. Thereby, the danger
degree acquired at S600 of the present embodiment becomes higher in
the "HIGH" level, as the danger hand-free duration becomes
longer.
Then, the present danger estimation process is ended, advancing the
processing to S160 of the hand-free driving warning process.
Effect of Second Embodiment
As explained above, in the driving assistance apparatus of the
present embodiment the warning is outputted more strongly as the
high danger position at which the non-grip hand exists becomes
farther away from the driver's seat.
The driving assistance apparatus of the present embodiment enables
the driver to recognize the association in which the danger degree
increases as the necessity of moving the body of the driver becomes
greater.
Other Embodiments
Up to this point, description has been given to an embodiment of
the present invention. However, the present invention is not
limited to the above embodiment, and it can be variously embodied
as long as not departing, from the subject matter of the present
invention.
For example, in the danger estimation map in the second embodiment,
the association between the detectable position and the danger
degree is provided such that the danger degree increases as the
detectable position requires more movement amount of the body for
the driver to cause the non-grip hand to exist or manipulate.
Without need to be limited thereto, the association between the
detectable position and the danger degree may be varied. That is,
the danger degree may be designed to increase as a time length
necessary for the non-grip hand to manipulate a target object which
exists in the detectable position and then reach the steering wheel
71 becomes longer. Further, the danger degree may be designed to
increase as a time length for which the driver moves the sight line
from the vehicle heading direction becomes longer when manipulating
the target object which exists in the high danger position.
When the former case is adopted, the association between the
detectable position and the danger degree may be provided, as
illustrated in FIG. 8A, such that the danger degree becomes greater
in the ascending order of the high danger position P2, the high
danger position P1, and the high danger position P3. In other
words, in the ascending order of the action to manipulate an
in-vehicle instrument located in the high danger position P2, the
action to manipulate an in-vehicle instrument located in the high
danger position P1, and the action of eating, drinking, smoking, or
calling in the high danger position P3 the necessity for the driver
to concentrate is estimated to be increased. The above actions are
estimated to decrease the consciousness of or concentration on the
driving of the subject vehicle.
In contrast, when the latter case is adopted, the association
between the detectable position and the danger degree may be
provided, as illustrated in FIG. 8B, such that the danger degree
becomes greater in the ascending order of the high danger position
P3, the high danger position P1 and the high danger position P2. In
other words, in the ascending order of the action of eating,
drinking, smoking, or calling at the high danger position P3, the
action to manipulate an in-vehicle instrument located in the high
danger position P1, and the action to manipulate an in-vehicle
instrument located in the high danger position P2, the duration or
time length for which the driver moves the sight line from the
vehicle heading direction is estimated to become longer. The above
actions are estimated to decrease the consciousness of or
concentration on the driving of the subject vehicle.
When those danger estimation maps are used to provide or define the
danger degree the driver of the subject vehicle can be made to be
able to recognize executing of the dangerous action against the
driving manipulation, enabling the driver to execute the safer
driving manipulation.
Further, in the driving assistance apparatus 1 of the above
embodiments, the image processing device 30 executes the image
processing. The navigation ECU 50 can execute the image processing.
That is, the position of the driver's hand may be specified by the
navigation ECU 50 instead of the image processing device 30.
Furthermore, in the driving assistance apparatus 1 of the above
embodiment the grip state of the steering wheel 71 is detected
based on the detection signal from the wheel grip sensor 12.
Without need to be limited thereto, another method of detecting the
grip state of the steering wheel 71 may be used. For instance, it
may be detected from a captured image. In this case, when the
driver's hand exists as overlapping on an area of the captured
image where the image of the steering wheel 71 (referred to as a
steering wheel area) is present it is determined that the steering
wheel 71 is gripped by a driver's hand. Further, in this case, when
the number of driver's hand overlapping on the steering wheel area
is two, it may be determined that the steering wheel 71 is gripped
by both the hands of the driver, i.e., in the both-hands grip
state. When the number of driver's hand overlapping on the steering
wheel area is one or zero, it may be determined that the grip state
of the steering wheel 71 is in the hand-free driving state.
The method of specifying the position of the driver's hand may be
not restricted to the method described in the above embodiments.
For example, as described in JP-A-2009-037534, the position of the
driver's hand may be specified as follows. Detecting a
characteristic point (for example, a wrist, elbow, or shoulder)
from the captured image; collating the detected characteristic
point with each action inference model previously prepared for
every action which the driver can execute; specifying the action
corresponding to the action inference model having the highest
degree in accordance; and defining, as a position of the driver's
hand, a position of the in-vehicle instrument manipulated by the
driver in the specified action.
In addition, at S160 of the above hand-free driving warning
process, the output of a warning is prohibited when the danger
degree is set in "LOW" level. However, the warning in the "LOW"
level of the danger degree is not limited thereto, but the output
of the warning may be made in a level much lower than "WEAK" level.
That is, the warning strength for the "LOW" level may be designed
as needed as long as the strength of the warning remains the
maximum strength as compared with other levels.
Furthermore, the warning in the hand-free driving warning process
of the above embodiments is outputted by changing the volume of the
sound outputted from the audio output portion 44. However, it may
be outputted by changing the cycle of the sound or tone of the
sound. In addition, not only the message or contents of the warning
are changed in the display portion 43, but also the character font
or figure may be changed in the display portion 43.
Although the hand-free driving warning process is executed by the
navigation ECU 50 in the driving assistance apparatus 1 of the
above embodiments, it may be executed by another apparatus such as
the image processor 35, for example.
[Functions]
The wheel grip sensor 12 of the above embodiment may function as a
grip state detection means or device. The image processing device
30 may function as an image acquisition means or device. S110, S120
in the hand-free driving warning process, and S210 to S240 in the
danger estimation process (or S510, S520, S550) may function as a
position specification means or section. Furthermore, S150 in the
hand-free driving warning process and S260, S290, and S300 (or
S540, S550, S600) in the danger estimation process may function as
a danger derivation means or section. S160 in the hand-free driving
warning process may function as a warning means or section.
Each or any combination of processes, functions, sections, steps,
or means explained in the above can be achieved as a software
section or unit (e.g., subroutine) and/or a hardware section or
unit (e.g., circuit or integrated circuit), including or not
including a function of a related device, furthermore, the hardware
section or unit can be constructed inside of a microcomputer.
Furthermore the software section or unit or any combinations of
multiple software sections or units can be included in a software
program, which can be contained in a non-transitory
computer-readable storage media or can be downloaded via a
communications network and then stored in a non-transitory
computer-readable storage media.
Aspects of the disclosure described herein are set out in the
following clauses.
As an aspect of the disclosure, a driving assistance apparatus for
a vehicle is provided as follows. A grip state detection section is
configured to detect a grip state of a steering wheel in a
compartment of the vehicle. An image acquisition section is
configured to acquire a captured image of the compartment that
covers a possible action range of a person who is seated in a
driver's seat. A position specification section is configured to
specify, based on a captured image acquired by the image
acquisition section, a position where a non-grip hand exists, the
non-grip hand being a hand that is separate from the steering
wheel, on condition that (i) the grip state of the steering wheel
is in a hand-free state, in which at least either of two hands is
separate from the steering wheel as a result of detecting of the
grip state detection section, and (ii) a travel state of the
vehicle is within a stipulated travel state, which is
predetermined. A danger derivation section is configured to derive
a danger degree such that the danger degree comes to have a greater
value as a degree of a danger against driving of the vehicle
becomes higher because the non-grip hand exists in a position
specified by the position specification section. A warning section
is configured to execute an output of a warning in a weaker state
as the danger degree derived by the danger derivation section comes
to have a smaller value.
As an optional aspect, the danger derivation section may classify
several positions in the compartment in the vehicle based on danger
degrees and define previously a low danger position within the
positions classified, wherein when the non-grip hand exists in the
low danger position, the danger degree has a value smaller than a
reference value. Furthermore the danger derivation section may then
derive the danger degree such that when the non-grip hand exists in
the low danger position, the danger degree has a value smaller as
compared with a case that the non-grip hand exists in a high danger
position, which is within the positions classified in the
compartment and is other than the low danger position.
According to the driving assistance apparatus, if the non-grip hand
exists in the low danger position, the warning outputted from the
warning section will become weak. Accordingly, the driver who puts
the non-grip hand in the low danger position during performing the
driving manipulation need not conscious of a warning outputted more
than needs, and can maintain the concentration on the driving
manipulation more certainly.
Further, the danger degree during driving the vehicle is decreased
as the duration (i.e., time length) for which either hand is
separate from the steering wheel becomes short.
Further, the danger derivation section may derive the danger degree
such that the danger degree comes to have a smaller value as a
non-grip hand existence duration for which the non-grip hand
continues to exist in the low danger position becomes shorter.
According to the above driving assistance apparatus, the danger
degree can be derived as a value adapted to the actual driving
manipulation in the vehicle. As a result, the above configuration
can reduce an output of a warning that may provide the driver with
the sense of discomfort.
Further to the above configuration the danger derivation section
may derive the danger degree such that when the non-grip hand
existence duration relative to the low danger position where the
non-grip hand exists is shorter than a predetermined value, the
danger degree has a minimum value.
Thus, if the non-grip hand exists in the low danger position, the
warning outputted from the warning section will become weakest. The
driver can maintain the concentration on the driving manipulation
more certainly. It is noted that the above predetermined value or
time may be defined as a very short duration for which to confirm
the fact that the non-grip hand existed in the low danger position
(for example, 0.1 or less second).
As an optional aspect, the danger derivation section may derive the
danger degree such that when the non-grip hand exists in the high
danger position, the danger degree comes to have a greater value as
a non-grip hand existence duration for which the non-grip hand
continues to exist in the high danger position becomes longer.
That is, the warning outputted from the warning section may become
stronger as the duration becomes longer, the duration for which the
non-grip hand is separate from the steering wheel while existing in
the high danger position providing the high degree of the danger
against the driving manipulation.
Therefore, the driver of the vehicle can recognize more certainly
the warning outputted based on the non-grip hand existing in the
high danger position. Further, the danger derivation section may
derive the danger degree such that the danger degree varies
step-wise in proportion to the duration or time length for which
the non-grip hand is existing in the high danger position.
The warning may be "audio data for sounding a warning message"
according to the danger degree, for example. In this case, the
above configuration can reduce the number of kinds of the audio
data previously prepared.
As an optional aspect, the danger derivation section may derive the
danger degree such that when the non-grip hand exists in the high
danger position, the danger degree comes to have a greater value as
the high danger position is farther away from the driver's
seat.
That is, the warning outputted by the warning section becomes
strong as the distance of the high danger position from the
steering wheel becomes larger or farther. The driving assistance
apparatus thus enables the driver to recognize that the danger
degree increases as the necessity of moving the body of the driver
becomes greater.
As an optional aspect, the high danger position may a position
where a target object manipulated by the non-grip hand exists.
Further, the danger derivation section may derive the danger degree
such that when the non-grip hand exists in the high danger
position, the danger degree comes to have a greater value as a
duration for which the non-grip hand manipulates the target object
in the high danger position and then grips the steering wheel is
estimated to become longer.
That is, when manipulating the target object which exists in the
position having higher danger degree, the warning outputted by the
warning section becomes strong. Thereby, the driver of the vehicle
can be made to recognize that the danger degree becomes greater, as
a result of the driver's consciousness concentrating on the
manipulation of the target object.
As an optional aspect, the high danger position may be a position
where a target object manipulated by the non-grip hand exists.
Further, the danger derivation section may derive the danger degree
such that when the non-grip hand exists in the high danger
position, the danger degree comes to have a greater value as a
duration for which the driver moves a sight line away from a
heading direction of the vehicle when manipulating the target
object in the high danger position is estimated to become
longer.
That is, when manipulating the target which exists in the position
having higher danger degree, the warning outputted by the warning
section becomes strong. Thereby, the driver of the vehicle can be
made to recognize that the danger degree becomes greater, as a
result of the driver's consciousness concentrating on the
manipulation of the target object.
As an optional aspect, the position specification section may
determine whether a position where the non-grip hand exists is the
low danger position, and define a high danger position which is
within the positions classified in the compartment and is
determined not to be the low danger position.
According to such a configuration, the positions where the non grip
hand may exist can be determined or defined as binary values, i.e.,
either the low danger position or the high danger position. Such a
configuration can reduce an amount of processing for specifying a
position of the non-grip hand.
As an optional aspect, the position specification section may
define as the low danger position, at least one of (i) an armrest
provided in the vehicle (ii) a window frame in the vehicle, and
(iii) a driver's upper thigh.
This is because as follows. The driver of the vehicle may put the
non-grip hand on the armrest or window frame provided in the
vehicle, or driver's upper thigh during the driving manipulation.
In such a case, while relaxing moderately, the driver of the
vehicle still concentrates on the driving manipulation, thereby
usually enabling the vehicle to be driven safely in many cases.
As an optional aspect, the warning section may prohibit an output
of a warning when the danger degree derived by the danger
derivation section is equal to or less than a predetermined
value.
According to the above configuration an unnecessary warning may be
more certainly prevented from being outputted during the driving
manipulation.
As an optional aspect, the stipulated travel state may be a travel
state where the hand-free state during driving of the vehicle is
evitable.
In other words, in a travel state other than the stipulated travel
state, the hand-free state during driving of the vehicle is
inevitable or permitted. For instance, the travel state other than
the stipulated travel state may include the following: the backward
moving state where the subject vehicle is moved backwardly; the
rotating state where the subject vehicle is rotated; the
indispensable instrument manipulating state where an indispensable
instrument is manipulated; the in-traffic congesting state where
the subject vehicle is involved in the traffic congestion; and the
slow speed state where the subject vehicle is in the low speed.
It will be obvious to those skilled in the art that various changes
may be made in the above-described embodiments of the present
invention. However, the scope of the present invention should be
determined by the following claims.
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